5.2 - Excretion

Question 1

What is excretion

Answer 1

The removal of metabolic products

Question 2

What happens to CO2 from respiration

Answer 2

Dissolves in blood plasma to make carbonic acid (H2CO3).
This dissociates to release H+ ions
Lowers the pH of the blood plasma that is detected by chemoreceptors in blood vessels and brain which cause an increased breathing and heart rate
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Question 3

What is the liver

Answer 3

A metabolic and excretory organ which removes excess and unwanted substances from the blood.
It has a high enzyme activity which release heat that warms our blood

Question 4

Hepatic artery

Answer 4

Carries oxygenated blood from the lungs to the liver

Question 5

Hepatic vein

Answer 5

Carries blood away from the liver to the heart

Question 6

Hepatic portal vein

Answer 6

Takes deoxygenated blood from the digestive system to the liver
Carries products from digestion: amino acids and monosaccharides

Question 7

Hepatocytes

Answer 7

Cells in the liver
Have a cuboidal shape and many microvilli
protein synthesis; metabolism and storage of bile; synthesis of bile and cholesterol and detoxification

Question 8

Lobules

Answer 8

Functional unit of the liver, in the shape of a hexagon to maximise surface area which ensure contact with the blood

Question 9

inter lobule vessels

Answer 9

Blood vessels are split into smaller and smaller vessels that run parallel to the lobules

Question 10

Sinusoid

Answer 10

Hepatic portal vein and artery branch blood mix together
Lined with hepatocytes removes unwanted substances from the blood
It is more leaky to allow blood to leave